Rivermatics

USGS Streamgage 13135500

Big Wood River near Ketchum, ID

Big Wood River near Ketchum, ID is USGS streamgage 13135500 in Idaho, monitoring river discharge in hydrologic subbasin 17040219. It sits on the Big Wood River, alongside 7 other gauges Rivermatics tracks on the same river. It drains a watershed of about 137 square miles. Discharge records at this site go back to 1948. Typical flow runs near 190.7 cfs in July and 136.1 cfs in April, with the higher of the two arriving in July. Rivermatics issues a daily machine-learned flow outlook for this gauge, reaching 14 days ahead.

View live conditions & forecast →

Gauge details

State
Idaho
Drainage area
137 sq mi
Subbasin (HUC-8)
17040219
Coordinates
43.78626, -114.42506
USGS site number
13135500
Records begin
1948-06-01 (78 years)
Rivermatics forecast
14-day flow outlook

14-day flow forecast

Based on observations through for Big Wood River near Ketchum, ID. Each day carries a median estimate and the band the model expects the flow to fall within — not a single number to plan against. Forecasts are re-issued daily; see the live screen for the current outlook.

Forecast daily mean discharge in cubic feet per second, by date
Date Low p10 Expected p50 High p90 Range
53.6 55.6 57.1
52.6 55 56.9
51.9 54.5 56.7
51.5 54.3 56.8
50.9 53.8 56.5
50.5 53.6 56.5
50.1 53.3 56.2
49.5 52.9 56
49 52.5 55.8
48.3 52 55.5
47.8 51.6 55.2
47.3 51.2 55
46.6 50.8 54.7
46.2 50.5 54.6

All values in cubic feet per second (cfs). Estimates only — do not use them for navigation or for any safety, rescue, or emergency decision.

Typical flow by month

Long-term daily discharge percentiles from the USGS record (up to 79 years of data), averaged within each month. These describe the historical normal range — they are not a forecast and not today's reading.

Historical monthly discharge percentiles in cubic feet per second
Month Low p10 Typical p50 High p90 Range
January 38 50 61.4
February 37.9 48.2 58.4
March 39.6 50.5 77
April 62.8 136.1 331.6
May 188.7 418.1 869.2
June 226.7 463.7 913.2
July 92.2 190.7 378.8
August 57.7 99 150.8
September 51.4 74.6 103.4
October 49.9 68.2 90.7
November 43.6 60.2 79.1
December 36.7 51.7 68.3

All values in cubic feet per second (cfs).

Common questions

When does Big Wood River near Ketchum, ID normally run highest?
June, on the long-term record. The median daily flow that month is about 463.7 cfs, against 48.2 cfs in February, the lowest month. These are historical normals for the date, not a forecast and not today's reading.
What is a normal flow for Big Wood River near Ketchum, ID?
It depends on the month. In January, half of days historically fall near 50 cfs, with the middle 80% of days between 38 and 61.4 cfs. The month-by-month table on this page gives the full range.
How long has Big Wood River near Ketchum, ID been measured?
Discharge records at USGS site 13135500 begin in 1948, about 78 years, covering roughly 5,585 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
Is there a flow forecast for Big Wood River near Ketchum, ID?
Yes. Rivermatics trains a machine-learned model — a temporal-fusion transformer — on this basin's observed flows, weather, and snowpack, and issues a daily flow outlook reaching 14 days ahead: a median estimate inside a confidence band, not a single number to bet on. Every forecast is scored against days the model never trained on, and that track record is published on the live gauge screen. Open live conditions to see the current outlook.
Where is Big Wood River near Ketchum, ID?
The gauge sits at 43.78626, -114.42506, in Idaho, in hydrologic subbasin 17040219, draining roughly 137 square miles.
Can I use Big Wood River near Ketchum, ID data for flood or safety decisions?
No. Rivermatics provides estimates, not guarantees, and the readings and forecasts here may be delayed, inaccurate, or wrong. Do not use them for navigation or for any safety, rescue, or emergency decision. Check the National Weather Service and USGS directly, and use your own judgment.

Upstream and downstream on the Big Wood River

Every gauge Rivermatics tracks on this river, ordered by drainage area — upstream first. See the Big Wood River in full.

Other gauges in this subbasin